^1,2Chen Li,^1,3Yang Li,²Kuixian Wei,^1,4huang Guo,⁴Rui Li,^1,3Xiongyao Li,^1,3Jianzhong Liu²Wenhui Ma
Geochimica et Cosmochimica Acta (in Press) Link to Article [https://doi.org/10.1016/j.gca.2024.06.038]
¹Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
²Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China
³Center for Excellence in Comparative Planetology, Chinese Academy of Sciences, Hefei 230026, China
⁴Institute of Remote Sensing and Geographical Information System, School of Earth and Space Sciences, Peking University, Beijing 100871, China
Copyright Elsevier

Lunar soil undergoes space weathering and accumulates optically active opaque particles (OAOpq) of different sizes, resulting in a darkening or red shift of the reflectance spectrum. The surfaces of weakly weathered objects exhibit spectral characteristics of strong weathering; these mechanisms are still unclear. The causes of OAOpq in lunar soil are complex, especially for submicrometer particles, which account for the largest mass proportion. We found ubiquitous impact-dispersed Fe–Fe1-xS core–shell particles in Chang’e-5 lunar soil impact glass and splatter. The crystal structure, particle size distribution, and chemical composition of OAOpq in the impact glass indicate that these OAOpq consist of sulfides or metals from multiple sources. Thermodynamic evidence, diffusion behavior, and particle dispersion characteristics indicate that impact dispersion is the most likely formation mechanism of these OAOpq. The proposed impact dispersion provides a reason for the large number of OAOpq and the limited products for in situ reactions. This process explains why lunar soil with a low degree of weathering exhibits substantial spectral modification properties. The results provide insights into space weathering of the lunar surface and also imply that impact-dispersed OAOpq may be the primary modification type on asteroid surfaces. The unique chemical properties of Fe–Fe1-xS OAOpq also indicate that the lunar regolith has the potential for resource utilization.